Ultra-sensitive molecularly imprinted electrochemical sensor for patulin detection based on a novel assembling strategy using Au@Cu-MOF/N-GQDs

This study introduces an innovative procedure for the development of a molecularly imprinted electrochemical sensor for ultra-sensitive and selective detection of patulin. Firstly, the surface of a glassy carbon electrode (GCE) was decorated by nitrogen doped graphene quantum dots (N-GQDs) and AuNPs-functionalized Cu-metal organic framework ([email protected]) and then a layer of molecularly imprinted polymer (MIP) was grown on [email protected]/N-GQDs/GCE by electropolymerization. Electrochemical techniques were used to characterize and study the electrochemical behavior of the MIP/[email protected]/N-GQDs/GCE, which exhibited a stable reference peak of [email protected] at −0.11 V after elution of patulin molecules. This peak current density decreased with rebinding of patulin molecules therefore it was considered as indicator signal. The designed MIP sensor presented a wide linear range from 0.001 to 70.0 ng mL−1, and a low detection limit (0.0007 ng mL−1). This newly developed method based on the synergistic effects of N-GQDs and [email protected] combined with MIP technique offered outstanding selectivity, sensitivity, stability, and reproducibility. The good accuracy (recovery%, 97.6–99.4) and high precision (RSD%, 1.23–4.61) of this sensing system for analysis of apple juices proved the high potential of it for rapid and low cost determination of patulin compared to chromatographic methods.